intransitive verb

(of a person or animal) emit a deep loud roar, typically in pain or anger.

he bellowed in agony

blare,boom,roar,thunder,bellow,pump,shriek,screech

noun

A deep roaring shout or sound.

a bellow of rage

roar,shout,bawl,bark,bay,yawp,yell,yelp,shriek,howl,scream,screech,call,cry,whoop,wail,caterwaul